diff options
Diffstat (limited to 'compiler-rt/lib/builtins/popcountdi2.c')
| -rw-r--r-- | compiler-rt/lib/builtins/popcountdi2.c | 34 |
1 files changed, 17 insertions, 17 deletions
diff --git a/compiler-rt/lib/builtins/popcountdi2.c b/compiler-rt/lib/builtins/popcountdi2.c index 09eeb9e9925..90c9fe714f6 100644 --- a/compiler-rt/lib/builtins/popcountdi2.c +++ b/compiler-rt/lib/builtins/popcountdi2.c @@ -15,21 +15,21 @@ /* Returns: count of 1 bits */ -COMPILER_RT_ABI si_int -__popcountdi2(di_int a) -{ - du_int x2 = (du_int)a; - x2 = x2 - ((x2 >> 1) & 0x5555555555555555uLL); - /* Every 2 bits holds the sum of every pair of bits (32) */ - x2 = ((x2 >> 2) & 0x3333333333333333uLL) + (x2 & 0x3333333333333333uLL); - /* Every 4 bits holds the sum of every 4-set of bits (3 significant bits) (16) */ - x2 = (x2 + (x2 >> 4)) & 0x0F0F0F0F0F0F0F0FuLL; - /* Every 8 bits holds the sum of every 8-set of bits (4 significant bits) (8) */ - su_int x = (su_int)(x2 + (x2 >> 32)); - /* The lower 32 bits hold four 16 bit sums (5 significant bits). */ - /* Upper 32 bits are garbage */ - x = x + (x >> 16); - /* The lower 16 bits hold two 32 bit sums (6 significant bits). */ - /* Upper 16 bits are garbage */ - return (x + (x >> 8)) & 0x0000007F; /* (7 significant bits) */ +COMPILER_RT_ABI si_int __popcountdi2(di_int a) { + du_int x2 = (du_int)a; + x2 = x2 - ((x2 >> 1) & 0x5555555555555555uLL); + /* Every 2 bits holds the sum of every pair of bits (32) */ + x2 = ((x2 >> 2) & 0x3333333333333333uLL) + (x2 & 0x3333333333333333uLL); + /* Every 4 bits holds the sum of every 4-set of bits (3 significant bits) (16) + */ + x2 = (x2 + (x2 >> 4)) & 0x0F0F0F0F0F0F0F0FuLL; + /* Every 8 bits holds the sum of every 8-set of bits (4 significant bits) (8) + */ + su_int x = (su_int)(x2 + (x2 >> 32)); + /* The lower 32 bits hold four 16 bit sums (5 significant bits). */ + /* Upper 32 bits are garbage */ + x = x + (x >> 16); + /* The lower 16 bits hold two 32 bit sums (6 significant bits). */ + /* Upper 16 bits are garbage */ + return (x + (x >> 8)) & 0x0000007F; /* (7 significant bits) */ } |

